1. Achuthan, S.B., Rao, S.B., Rao, A.R., 1982. The number of symmetric edges in a digraph with prescribed out-degrees. In: Vijayan, K.S., Singhi, N.M. (Eds.), Proceedings of the Seminar on Combinatorics and Applications in honour of Professor S.S. Shrikhande on his 65th Birthday. Indian Statistical Institute, Calcutta.
2. Borgatti, S.P., 1994. ANTHROPAC 4.72/X. Analytic Technologies, Columbia, SC.
3. Borgatti, S.P., Everett, M., Freeman, L.C., 1993. UCINET IV 1.66/X. Analytic Technologies, Columbia, SC.
4. Brewer, D.D., 2000. Forgetting in the recall-based elicitation of personal and social networks. Unpublished manuscript, Alcohol and Drug Abuse Institute, University of Washington.
5. What do we mean by friend? An inductive study;Fischer;Social Networks,1982